Lectins from the marine annelid, Nereis stimulate sperm motility, dissociate the head from the flagellum and agglutinate sperm head-to-head. The lectins will be purified by affinity chromatography on N-acetylgalactosamine-agarose. Further purification should produce individual lectins responsible for the motility effect, agglutination and/or head-tail dissociation. The effect of lectins on motility will be examined in epididymal, seminal, capacitated and fertilizing sperm. Correlative studies on lectin binding to the sperm surface will be carried out by fluorescence and electron microscopic localization of marked lectins. The property that dissociates the head will be explored in experiments designed to test the lectins as an anti-fertility agent.